Domestic electric appliance

ABSTRACT

A domestic appliance has a heated heat transfer member located in or on its housing and a temperature sensor for measuring the operating temperature of the transfer member. User inputs are provided for selecting an optimized temperature setting for the transfer member. A temperature controller controls the operating temperature of the heat transfer member in response to signals from the temperature sensor to maintain it at or near the selected temperature setting. The power cord of the appliance has a plug top with electrical pins for connection with a wall outlet. The power cord is coiled on a spring-loaded spool within the plug top and is extendable from the plug top. The spring-loaded spool provides a retracting force to retract the power cord back within the plug top.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to domestic electric appliances and in particular to temperature control of domestic appliances.

2. Background Information

Many domestic appliances have a temperature controller and heating element connected to a heat transfer member for providing an operating heat output. Two common examples are electric irons and garment steamers.

Typically the temperature control is a dial thermostat connected to a temperature sensor positioned with the heat transfer member. The thermostat is marked with temperature ranges suitable for the function being performed. In the case of an iron this is pressing different types of fabric, for example nylon, silk, wool, cotton or linen. In use the user of the iron turns the thermostat to a position suitable for the fabric to be pressed. A Light-Emitting-Diode (LED) is provided on or near the thermostat to indicate when power is being supplied to the heating element.

Two problems exist with this temperature setting arrangement. Firstly, the set temperature is not exact because the markings only provide an indicative range and not an exact position for the thermostat. The user may not always position the thermostat at the same position each time they use the appliance. Furthermore, during use of the appliance the thermostat dial may be inadvertently moved, or there may be inherent inaccuracies in the thermostat mechanism.

The second problem is that the indicator LED is typically connected to the terminals of the heating element so that when power is applied to the heating element the LED is illuminated. When the heat transfer member reaches the set temperature the thermostat disconnects power to the heating element and the LED goes out. This tells the user that the heat transfer member has reached the set thermostat temperature however there is no way for the user to tell what temperature the heat transfer member has reached before the LED goes out.

SUMMARY OF THE INVENTION

It is an object of the present invention to overcome or substantially ameliorate at least one of the above problems and/or more generally to provide improved temperature control of domestic appliances.

There is disclosed herein a domestic appliance, preferably but not exclusively an iron, comprising a housing, a heat transfer member located in or on the housing, a heating element located with the heat transfer member for heating the member to an operating temperature, a temperature sensor located to measure the operating temperature, user inputs provided on the housing, and a temperature controller having a plurality of optimized temperature settings and operating the heating element in response to user inputs and signals from the temperature sensor to maintain the operating temperature of the heat transfer member at or near one of the optimized temperatures settings.

Preferably, the temperature controller is an electronic device.

Preferably, the user inputs are push button switches coupled to the electronic temperature controller for selecting one of the optimized temperature settings.

Preferably, the appliance includes a first indicator for indicating one of the optimized temperature settings and a second indicator for indicating the operating temperature of the heat transfer member.

Preferably, the optimized temperature settings are optimized for a plurality of respective functional uses of the appliance.

Preferably, the appliance includes a power cord for supplying power to the appliance and a plug top coupled to the power cord for connecting the power cord to an electrical wall outlet, the plug top comprising a housing having electrical pins for electrical connection with electrical connectors of the electrical wall outlet and a spring-loaded spool on which the power cord can be coiled within the plug top housing, and wherein the power cord is extendable from the housing and the spring-loaded spool provides a retracting force to retract the power cord back within the housing.

Preferably, the plug top further comprises a brake for maintaining the power cord in the extended position and a brake release for releasing the brake so that the retracting force retracts the power cord back within the housing.

Preferably, the brake release comprises a button located on the plug top housing.

There is also disclosed herein a temperature controller for a domestic appliance, having a plurality of optimized temperature settings and operating a heating element of the appliance in response to user inputs and signals from a temperature sensor to maintain the operating temperature of the heating element at or near one of the optimized temperatures settings.

Further aspects of the invention will become apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the present invention will now be described by way of example and with reference to the accompanying drawings. The embodiment is an electric iron, but the invention may be applied to other domestic appliances. In the accompanying drawings:

FIG. 1 is a perspective view of an electric iron,

FIG. 2 is a first embodiment of temperature controls for the iron,

FIG. 3 is a second embodiment of temperature controls for the iron,

FIG. 4 is a retractable cord assembly for a domestic appliance,

FIG. 5 is a sectional view of the cord assembly spool, and

FIG. 6 is the electric iron with retractable cord assembly.

DETAILED DESCRIPTION OF THE DRAWINGS

In the accompanying drawings there is depicted an electric iron comprise a housing 1 having a handle 2 integrally formed at an upper part thereof and a heat plate, or soleplate, 3 positioned at a lower part thereof. A heating element is positioned with the soleplate 3 for heating it. A power cord 4 extends from the base 5 of the handle 2 for connecting the iron to a power outlet/wall socket (not shown). A stand, or foot, 6 is provided proximate the base 5 of the handle 4 for allowing the iron to rest in an upright position during heating or pressing rest periods. The above configuration is substantially as known and may include an internal water tank, and a water jet/steam outlet 7 on the front of housing 1 and steam outlets on soleplate 3.

An electronic temperature controller 8 is located on top of the handle 2. The temperature controller 8 is depicted in FIGS. 2 and 3. It includes two columns of LED indicators 9, 10. In the illustrated embodiment each column has five LEDs 9, 10. One LED 9, 10 from each column is visually associated with a symbol or label representing one of five fabric types. The fabric types are linen 11, cotton 12, wool 13, silk 14, and nylon 15. The symbols/labels are positioned between an LED from each column 9, 10. The first column of LEDs 9 indicates a temperature selected by a user. The second column of LEDs 10 represents the temperature of the soleplate 3.

The controller has a discrete predetermined temperature setting for each of the five fabric types linen 11, cotton 12, wool 13, silk 4, and nylon 15. The predetermined temperature settings are optimised temperatures for pressing the respective fabric type. The temperature controller 8 includes a temperature setter 16 for selecting the temperature setting. The temperature setter 16 comprises a temperature raise switch 17, a temperature lower switch 18 and an element power indicator LED 21. As the user successively presses the raise switch 17 of the setter 16 the LEDs 9 successively illuminate from the lowest temperature setting, for nylon 15, to the highest setting, for linen 11, to indicate the selection. The selected setting can be lowered using the temperature lower switch 18.

The temperature controller 8 also includes a steam setting switch 19, steam burst switch 22 and spray switch 20 but these are not critical to the invention.

The controller 8 operates to control power to the heating element, and thus the temperature of the soleplate 3, in response to the user selected temperature setting and signals from a temperature sensor on the soleplate 8. The temperature of the soleplate 3 is indicated by LEDs 10 in the second column. As the soleplate 3 reaches the predetermined operating temperature of a fabric type the corresponding LED 10 is illuminated.

In use, the power cord is plugged into a wall socket and the user selects the fabric to be pressed by pressing the temperature rise 17 and/or temperature lower 18 buttons. An LED 9 from the first column illuminates to indicate which fabric, linen 11, cotton 12, wool 13, silk 4, or nylon 15, has been selected. Each fabric is associated with its predetermined optimum pressing temperature. Power is supplied to the heating element and LED indicator 21 on temperature setter 16 illuminates to indicate that the heating elements are on. As the temperature of the soleplate 3 begins to rise the controller 8 illuminates an LED from second column 10 in response to signals from the temperature sensor. The illuminated LED in the second column 10 indicates an actual temperature reached by the soleplate 3.

For example, if a user desires to press a woollen garment/fabric they press the temperature rises button 17 three times. The first press of button 17 illuminates the first LED in column 9 adjacent nylon symbol 15. The second press of button 17 illuminates the second LED in column 9 adjacent the silk symbol 14. The third press of button 17 illuminates the third LED in column 9 adjacent the wool symbol 13. The operating temperature is set to the predetermined temperature for wool fabrics. Power is supplied to the heating elements and LED indicator 21 illuminates. When the soleplate temperature reaches the predetermined optimum temperature for nylon the first LED in second column 10 adjacent nylon symbol 15 illuminates. When the soleplate temperature reaches the predetermined optimum temperature for silk the second LED in second column 10 adjacent silk symbol 14 illuminates. When the soleplate temperature reaches the predetermined optimum temperature for wool the third LED in second column 10 adjacent wool symbol 13 illuminates. The heating element is turned off and LED 21 goes out. The controller 8 cycles the heating element on and off in known manner to maintain the soleplate temperature at or near the predetermined optimum temperature for wool. LED 21 is illuminated to indicate when the heating element is on.

In the preferred embodiment only one LED 9, 10 in each column is illuminated at any one time. When an LED adjacent a symbol is turned on the previous illuminated LED in that column is turned off. In an alternative embodiment more than one LED 9, 10 in each column may be illuminated such that when the optimum temperature for, say, wool is reached the three LEDs in each column 9, 10 adjacent nylon 15, silk 14, and wool 13 symbols are illuminated simultaneously.

The controller 8 allows an optimised predetermined temperature setting to be selected easily and accurately and provides the user with feedback information to easily monitor the operating temperature of the appliance.

A plug top 23 connected to the cord 4 for connecting the iron to the power outlet/wall socket includes a housing 24 provided with electrical pins 25, 25′ extending from one end. The pins 25, 25′ are of a known type for electrical connection with the electrical connectors of the power outlet/wall socket. Positioned within the housing 24 is a rotational spool 26 on which the cord 4 is stored. The cord is stored neatly in a coil 27 to prevent twists. A coiled torsion spring 28 is coaxially coupled to the spool 26 for storing retraction energy when the cord 4 is extended from the spool 26. A brake 29 with release button 30 maintains the spool 26 in the desired position when the cord 4 is extended. When the release button 30 is presses the spring 28 provides a retracting force to rotate the spool 28 to rewind the cord 4 to the stored position 27. In use, a sufficient length of cord 4 is extended from the spool 26 for use of the iron. Excess cord is housed neatly and safely inside the plug housing 24 against the power outlet/wall socket.

Power is coupled from the electrical pins 25, 25′ to the cord 4 via a pair of continuous conductive slip-rings 31, 32 located on the spool 26 and a pair of conductive contacts 33, 34 located with the housing 24. The contacts are coupled to the pins 25, 25′ and the slip-rings 31, 32 are coupled to the power cord 4.

Modifications and alterations obvious to those skilled in the art are not to be considered as beyond the scope of the present intention. 

1. A domestic appliance comprising: a housing, a heat transfer member located in or on the housing, a heating element located with the heat transfer member for heating the member to an operating temperature, a temperature sensor located to measure the operating temperature, user inputs provided on the housing, and a temperature controller having a plurality of optimized temperature settings and operating the heating element in response to user inputs and signals from the temperature sensor to maintain the operating temperature of the heat transfer member at or near one of the optimized temperatures settings.
 2. The domestic appliance of claim 1 wherein the temperature controller is an electronic device.
 3. The domestic appliance of claim 2 wherein the user inputs are push button switches coupled to the electronic temperature controller for selecting one of the optimized temperature settings.
 4. The domestic appliance of claim 1 further including a first indicator for indicating one of the optimized temperature settings and a second indicator for indicating the operating temperature of the heat transfer member.
 5. The domestic appliance of claim 1 wherein the optimized temperature settings are optimized for a plurality of respective functional uses of the appliance.
 6. The domestic appliance of claim 1 further comprising a power cord for supplying power to the appliance and a plug top coupled to the power cord for connecting the power cord to an electrical wall outlet, the plug top comprising a housing having electrical pins for electrical connection with electrical connectors of the electrical wall outlet and a spring-loaded spool on which the power cord can be coiled within the plug top housing, and wherein the power cord is extendable from the housing and the spring-loaded spool provides a retracting force to retract the power cord back within the housing.
 7. The domestic appliance of claim 1 wherein the plug top further comprises a brake for maintaining the power cord in the extended position and a brake release for releasing the brake so that the retracting force retracts the power cord back within the housing.
 8. The domestic appliance of claim 1 wherein the brake release comprises a button located on the plug top housing.
 9. The domestic appliance of claim 1 being an iron wherein the heat transfer member is a soleplate.
 10. An electric iron comprising: a housing, a soleplate at an underside of the housing, a heating element located with the soleplate for heating the soleplate to an operating temperature, a temperature sensor located with the soleplate, user inputs provided on the housing, and a temperature controller having a plurality of discrete optimized temperature settings and operating the heating element in response to user inputs and signals from the temperature sensor to maintain the operating temperature of the soleplate at or near one of the optimized temperatures settings.
 11. A temperature controller for a domestic appliance having a heating element with an operating temperature and a temperature sensor located to measure the operating temperature, the temperature controller having a plurality of optimized temperature settings and operating the heating element in response to user inputs and signals from the temperature sensor to maintain the operating temperature of the heat element at or near one of the optimized temperatures settings. 